Die casting and injection molding are popular methods for manufacturing articles from metallic alloys, plastics, synthetic materials and other manufacturing materials, especially for thin walled and small parts. In hot chamber die casting, for example, molten zinc or magnesium is pushed from a crucible, or pot, into a die casting system through a nozzle. The molten metal enters the die casting system through a sprue where it then travels through a runner system before entering the die or mold cavity. Injection molding and die casting generally incorporate two-stage systems comprising a stationary die half and a movable die half, between which is located the die cavity. The stationary die half is fixed in position and includes a first portion of the die cavity into which plastic or molten metal is injected into for curing or solidification. The movable die half moves relative to the stationary die half and includes a second portion of the die cavity that mates with the first portion such that the article can be formed. Typically such articles include hollowed regions or complex features such as contouring or texturing. In order to create these features, it is necessary to insert a core object into the die cavity to produce a void. During a molding or casting cycle, the movable die half mates with the stationary die half whereby the manufacturing material can be injected into the cavity to produce an article having the shape of the cavity, including the void. After solidification or curing, the movable die half retracts from the stationary die half so that the manufactured article can be removed, whereby it is also necessary to remove the core object from the manufactured article.
In some injection molding and die casting systems, a slide assembly is used to produce the internal features within the cavity. In a slide assembly, the core object typically comprises a core pin, or another such projection, that extends into the die cavity from within either the stationary or movable die half. In slide assemblies, the relative movement of the die halves is used to pull the core pin from the die cavity. Typically, the slide assembly includes an angled cam pin that pushes and pulls the core pin in one direction as the die halves are moved in a perpendicular direction. In other words, the one-way or vertical motion of the die halves is translated into a perpendicular or lateral motion to move the core pin. As the die halves are brought together, the slide assembly pushes the core pin into the cavity such that the manufacturing material will form around it to produce the void or contour. After completion of the injection process, the core pin is pulled out of the manufactured article as the die halves separate such that the manufactured article can be removed from the cavity. In order to ensure full withdrawal of the core pin, the length of stroke of the core pin is directly proportional to the angle of the cam pin. However, the greater the angle of the cam pin, the more stress is produced in the cam pin as the die halves are pulled apart, thus resulting in a high occurrence of breakage. Typical slide assemblies are therefore limited in their stroke lengths, which limits the size of the feature that can be produced in the die cavity. As such, there is a need for improved slide assemblies.